Worth running seperate timers for "cool off" period?

[hwy17]

The hayward aquatrol system includes a pump power plug, so that the built in timer controls both the SWCG and the pump.

I would enjoy this feature, it would save me having to watch two timers to make sure they stay in sync.

However, I have two concerns about it. One being the reports of burnt up components from the pump power draw, and two being that Orenda recommends "cool down" flow after the cell turns off as a way to avoid potential calcium carbonate buildup on the cell plates (along with keeping water CSI slightly negative).

Do you think that the built in timer already includes any cool down period? If it doesn't I will suffer two timers, if they're both grid synced I think they should agree.

Hayward AquaTrol SWG - Further Reading

www.troublefreepool.com

 

[ajw22]

Oreanda has some strange views on water chemistry. Letting a SWG have a cool down time is one of the stranger ones. If the Hayward cell needed it then Hayward would recommend it and their controllers would do it. They don’t.

We have thousands of SWG users here and no SWG does a cool down. It is not necessary.

 

[hwy17]

The cool down they propose is not literally temperature related but to make sure there's no leftover sodium hydroxide hanging out in the plumbing as it sits there.

Calcium Flakes in Saltwater Pools

Saltwater pools often have white flakes in them. They are calcium flakes that form in the salt chlorine generator. This article explains why it happens.

blog.orendatech.com

Makes sense to me, and I don't have great faith that Hayward would really care about a subtle difference in deposit formation.

 

[ajw22]

You are free to run your pool anyway you want. It is not something we recommend and no one here does it.

 

[mgtfp]

It's actually standard with the Australian Astralpool SWGs. The pump is plugged into a power point in the SWG control unit, and the pump gets switched on and off by the SWG.

They have a so called pre-purge period of 5 minutes to ensure that the pump is primed before the cell starts producing. At the end, there is a post-purge period, where the cell turns off, but the pump keeps running for another 2 minutes. I always thought the purpose of this post-purge is to ensure that all hydrogen bubbles get blown out before the pump stops. A side bonus might be that after the post-purge, the water inside the cell has the same pH as the main water body, but I don't think it's that important. The high pH that creates cell scaling is in my understanding really close to the cathode electrodes, once the cell stops that should dissipate pretty quickly.

The default times of pre- and post-purge can be adjusted or turned off via the hidden service setup.

 

[JoyfulNoise]

There is no “cool down” time needed for an SWG, that is utter nonsense. From an electrochemical standpoint, the second you switch off the power to the cell, all chemical reactions cease. There is not some huge concentration of hydroxide that builds up anywhere in the cell and pool water has sufficient chemical buffering that the pH will return to normal bulk levels fairly quickly.

Orenda has “borrowed” lots of concepts from TFP over the years but their knowledge of chemistry is very poor. They take simple chemistry concepts and make them overly complex for no reason. Given that their primary purpose is to sell chemicals, their methods and recommendations are devised to further that end, not make pool care easier for the everyday pool owner.

 

[hwy17]

the second you switch off the power to the cell, all chemical reactions cease. There is not some huge concentration of hydroxide that builds up anywhere in the cell and pool water has sufficient chemical buffering that the pH will return to normal bulk levels fairly quickly.

If the pump power and cell power are switched off at exactly the same time it seems plausible that whatever localized effect the cell is having on the water's ph would then sit there in the cell body. But if you are saying that the effect is so localized to the surface of the plates of the cell that the liter of water surrounding them it is sufficient to buffer it I would understand the suggested concept.

Now that I've got to thinking about it in detail, even if I decide I personally believe in a benefit to washout, my solar system will provide me with plenty of that anyway. It takes about 30s after the pump shuts off for all the panel water to drain and it will be coming down and out through the cell.

The only remaining question then would be the reports of burnt up pump outputs on the controller. I would rather not risk my controller unit just for pump timing. But my pump only pulls about 5 amps and people are probably burning them up with 1.5HP.